The double star HD 87643

Observations made with ESO's Very Large Telescope Interferometer allowed a team of astronomers to discover that the star HD 87643, which lies at the centre of a dusty nebula, has a companion located about 50 times the mean Earth-Sun distance. This companion completes an orbit in a few tens of years and may be responsible for the regular ejections of material that created the nebula. By combining the light from various combinations of three of the telescopes forming the VLT array, the interferometric technique reveals details 100 times smaller than shown with the NACO adaptive optics instrument. The field of view is only 100 milli-arcseconds, or less than one third of a single WFI pixel.